Phase change materials (“PCM”) operate on the principle that a material requires a relatively significant amount of energy (heat) to change from a solid to a liquid and then back from a liquid to a solid. PCM can therefore absorb large amounts of heat or energy from their environment and return large amounts of heat to their environment. This effective absorption, store and release of heat can be used to regulate the temperature of an environment.
PCM has been used in various applications ranging from household insulation to clothing. For example, U.S. Pat. No. 5,637,389 to Colvin et al. discloses an insulative pad for a shoe insole including microcapsules containing a phase change material in a polymeric base layer. U.S. Pat. No. 5,499,460 to Bryant and Colvin discloses another such insulative pad for shoe insoles. U.S. Pat. No. 6,183,855 to Buckley discloses a composite material having a flexible matrix containing a phase change storage material. Buckley discloses using the composite material in wet suits, boot liners, socks, gloves, face masks and a metabolic heating or cooling blanket.
U.S. Pat. No. 6,699,266 to Lachenburch et al. discloses a bed mattress including PCM. The PCM is distributed in a gel or viscous fluid carrier in a thermal layer of the mattress. The thermal layer includes a conforming envelope containing the phase change material in the fluid carrier. U.S. Pat. No. 7,191,478 to Schmidt discloses a sleeping device including a layer of a material having temperature regulating properties and a layer of down filling. In Schmidt, a substrate is coated with a phase change material or a fiber is manufactured incorporating the phase change material to make the temperature regulating layer. The temperature regulating layer is split into channels by splitting walls and down filling is put into the channels.
It is therefore desired to develop a way to obtain the benefits of PCM in bedding products without requiring fluid envelopes or channels within the bedding product. It is further desired to provide bedding products with a substantial layer of PCM not achievable by use of fluid carriers or coatings. It is further desired to provide bedding products with an even and consistent distribution of PCM that is cost effective and easy to manufacture.